Conventionally, there are various products containing a crosslinked polymer such as contact lenses, paints and varnishes, and the like. However, in the crosslinked polymer, the distance from a crosslinked point to the next crosslinked point is not uniform; thus, when strain is applied to the crosslinked polymer, a site of a shorter distance between crosslinked points is broken preferentially, causing non-uniform breaking. For example, in the case of a paint or varnish, strain corresponds to force generated by drying after painting, and there is a problem of occurrence of crack on an applied surface after drying. In the case of a contact lens, there is a possibility of application of strain to the lens in use, generating a problem of occurrence of scratch on a lens surface.
On the other hand, Patent Document 1 discloses a crosslinked polyrotaxane, which is formed by crosslinking polyrotaxanes, each of which is comprised of pseudopolyrotaxane, which comprises a linear molecule (axis) and cyclic molecules (rota) in which the linear molecule is included in cavities of cyclic molecules in a skewered manner, and capping groups, each of which locates at each end of the pseudopolyrotaxane (each end of the linear molecule) in order to prevent the dissociation of the cyclic molecules. The crosslinked polyrotaxane has viscoelasticity generated by the movement of a cyclic molecule. Thus, even if strain is applied to the crosslinked polyrotaxane, the strain is dispersed uniformly in the crosslinked polyrotaxane by this action. Therefore, crack or scratch is not generated, differing from the crosslinked polymer. However, in a case where a material is constituted only of crosslinked polyrotaxane, there occurs a problem of relatively high cost. Further, only with the crosslinked polyrotaxane, a property required for a material to be applied is not obtained in some cases.    Patent Document 1: Japanese Patent No. 3475252.